The semiconductor integrated circuit industry has experienced rapid growth in the past several decades. Technological advances in semiconductor materials and design have produced increasingly smaller and more complex circuits. These material and design advances have been made possible as the technologies related to processing and manufacturing have also undergone technical advances. In the course of semiconductor evolution, the number of interconnected devices per unit of area has increased as the feature size has decreased. The semiconductor integrated circuit industry has produced numerous developments in effort to continue the process of scaling. One of the developments is the replacement or supplementation of the conventional planar metal-oxide-semiconductor field-effect transistor by the vertical field-effect transistor. However, existing vertical field-effect transistors have not been satisfactory in all aspects.